The invention relates to the use of a reactive diluent in common coating compositions made up of hydroxy-functional resins which are curable, by means of an aminoplast or phenolic resin, upon heating in the presence of a strong acid catalyst. Presently, low boiling diluents are employed as solvents for coating compositions and are removed upon heating said compositions in the curing process.
In U.S. Pat. No. 3,238,160, alkyd resins are cured with various formaldehyde based resins from a solvent of 150.degree. C.-300.degree. C. boiling point. The amount of solvent is at least 2-3 times the amounts employed herein. U.S. Pat. No. 3,920,595 teaches solvent based alkyds cured with aminoplast resins. The solvents described are alkanols and polyols. U.S. Pat. No. 4,038,225 shows hydrocarbons, alkanols and low-boiling glycol ethers as solvents for an alkyd-aminoplast coating system.